Abstract

Enhancement of light outcoupling into substrate modes by a grid of low-refractive-index material embedded into the organic layer of an organic light-emitting device(OLED) is analyzed using full-wave electromagnetic simulations. The low-index grid (LIG) redirects modes normally trapped within the high-index organic and indium tin oxide layers (waveguide modes) into the substrate where they can be further extracted into free space using methods such as microlens arrays or roughened surfaces. This increases the external quantum and power efficiencies without affecting the electroluminescent spectrum. The dependence on grid geometry, dimensions, and refractive index is explored to optimize the structure. Simulations show that up to 50% more light can be extracted from the high-index region using an ultralow-index grid than a conventional device, and provided efficient substrate-to-air outcoupling, the external quantum efficiencies of LIG OLEDs can reach .

Abstract

Enhancement of light outcoupling into substrate modes by a grid of low-refractive-index material embedded into the organic layer of an organic light-emitting device(OLED) is analyzed using full-wave electromagnetic simulations. The low-index grid (LIG) redirects modes normally trapped within the high-index organic and indium tin oxide layers (waveguide modes) into the substrate where they can be further extracted into free space using methods such as microlens arrays or roughened surfaces. This increases the external quantum and power efficiencies without affecting the electroluminescent spectrum. The dependence on grid geometry, dimensions, and refractive index is explored to optimize the structure. Simulations show that up to 50% more light can be extracted from the high-index region using an ultralow-index grid than a conventional device, and provided efficient substrate-to-air outcoupling, the external quantum efficiencies of LIG OLEDs can reach .